One important distinction between VBScript and VBA is that VBScript does not support ArcObjects because the ArcObjects classes do not implement
IDispatch. See the "IDispatch interface" section of Introduction to COM in the VBA SDK help for more info.
Another is that VBScript does not allow or require the
Dim'ing of variables of a specific data type (all variables are of type Variant in VBScript, so use Set only).
You can however use the Geoprocessing framework with VBScript, although it is not well documented or supported, as Python has become the favored scripting language for ArcGIS.
See the "Creating the geoprocessor with Perl, VBScript, or JScript" section of Creating the Geoprocessor Object in the ArcGIS Desktop help:
Set gp = WScript.CreateObject("esriGeoprocessing.GPDispatch.1")
gp.workspace = "c:/Tongass"
gp.clip "standb4", "clipcov", "standb4_clip", "POLY", "1.25"
You might find VBScript geoprocessing script examples on the old ArcScripts and the archived ESRI forums.
But my suggestion is to leave both VBScript and VBA behind and learn Python, or a compiled language such as VB.NET, C#, Java, or C++ instead.